Colour and Vision

1
Colour and Vision

• Sylvie Cringle
• Orthoptist

2
Orthoptists What we do!

• Diagnosis and management of disorders of visual
  development, binocular vision and ocular motility

3
Orthoptists an extended role.

• Treatment of patients with Specific Learning
  Difficulties, other reading difficulties and
  other visual disturbances

4
Background

• Degree Research Project
• Pursuit of interest at Heart of England NHS Trust
• Courses/study
• BIOS SLD SIG

5
Reading Difficulties

• General Learning difficulty
• Low intelligence
• Medical reason
• Specific Learning difficulty
• Dyslexia
• Meares Irlen Syndrome (Visual Stress)
• Other causes
• Physical disabilities such as poor vision or
  hearing
• Lack of knowledge of the English language
• Lack of exposure to printed material
• Lack of important pre-reading skills such as the
  ability to recognize letters and the ability to
  attach sounds to letters.

6
Dyslexia What is it?

• Literally Word Blindness
• 4 of GB population severely affected
• Affects boys 3 times more than girls
• Genetic component
• Normal or above average intelligence
• Difficulty in reading/writing
• Often not diagnosed and children left to struggle

7
Dyslexia General signs and symptoms

• Difficulties with
• Reading, writing and spelling
• Sequences
• Short term memory
• Copying
• Mental arithmetic
• Directions Left and Right

• Reverses numbers and letters
• Cant put ideas onto paper
• Frustration
• Lack of confidence
• Likes practical not academic subjects
• Dislikes reading

8
Meares Irlen Syndrome (Visual Stress) Signs and
Symptoms

• Some of the main symptoms are
• Glare from the page
• Headaches when reading
• Sore eyes when reading
• Movement/blurring of print

• Signs include
• Rubbing eyes when reading
• Excessive blinking
• Tiring/inability to read for long/ poor
  concentration
• Loses place
• Dislike of reading

9
What causes the visual disturbances?

• Two theories
• Hyper-excitability in Visual Cortex (Pattern
  Glare)
• Disorder of Visual Magnocellular system

10
Pattern Glare

• Exaggeration of normal phenomenon
• Visual symptoms when viewing stripes depends on
  spatial frequency of the stripes
• Spatial frequency of 3 cycles per degree
• Uncomfortable patterns visual distortions
• Symptoms alleviated by coloured filters

11
Visual Magnocellular System

• Directs visual attention and eye movements to
  identify letter order
• Visual magnocellular weaknesses may cause visual
  perceptual instability, hence letter position
  confusions
• Magnocells maximally activated by medium and long
  wavelengths (yellow)

12
Assessment of patients with reading difficulties
at H of E NHS Trust

• Referrals received
• Questionnaire sent to bring completed to
  appointment along with book
• Orthoptic assessment with additional tests
• Observation/assessment of reading
• In line with the BIOS SLD clinical guidelines

13
Orthoptic Assessment

• Accommodation
• Fusion
• Stereopsis
• Measurement
• Observation of reading
• Posture and movement
• Eye movements
• Types of Errors
• Dominant eye
• Assessment with Coloured Overlays

• Detailed history
• From child as well as parents
• Visual Acuity
• Distance
• Near
• With un-crowded test?
• Cover Test
• Ocular Movements
• Convergence

14
Management

• Appropriate Refractive correction
• Orthoptic Exercises or other treatment
• Convergence
• Accommodation
• Fusional reserves
• Tracking
• Occulsion
• Coloured overlay trial

• Practical advice
• Movement whilst reading
• Font type and colour
• Coloured pens/paper/computer screen colour
• Position in class
• Liase with class teacher/SENCO
• Colorimetry and Precision Tinted lenses

15
Case One The Double Whammy

• 70 year old Male
• ARMD
• RVA 6/38 LVA 6/24
• Unable to drive
• Struggling to read
• Magnifier helps
• Additional symptoms of movement of print
• Orthoptically satisfactory
• Chose purple overlay which relieved symptoms
• Known Dyslexic

16
Case Two Unexplained visual symptoms

• 30 year old female, Librarian
• Referred from main clinic
• Normal Ophthalmological examination
• Low myopic/astigmatic correction
• Symptoms
• Uncomfortable in bright light
• Movement of print
• Shadowing/halo around print
• Tired Eyes
• Frontal Headaches

17
Case Two Unexplained visual symptoms

• VAs R and L 0.3 (6/12) great discomfort
• Eyes more comfortable with unilluminated chart
• Orthoptically satisfactory, just Slight CI
• Chose lime green and mint green overlays
• VAs immediately improved with these to
• R and L 0.1 (6/7.5) and symptoms decreased.

18
Case Two Unexplained visual symptoms

• 3/12 review
• RVA 0.3 (6/12) LVA 0.4 (6/15) BL
• RVA 0.1 (6/7.5) LVA 0.2 (6/9.5) u/c Keeler
• Overlays do help but impractical for her job
  used at home for reading
• Offered referral for Colorimetry assessment with
  possibility of precision tinted lenses.

19
Case Two Unexplained visual symptoms

• On discharge
• RVA -0.1 (6/4.8) LVA 0.0 (6/6) BL
• Read with ease, no discomfort
• Symptoms now less
• Eyes less tired
• Overlays help with reading at home
• Not keen for Precision tinted lenses - cosmetic
  issue

20
Case Three Unexplained reduced VAs

• 5 year old Male (A)
• Referred by community optician
• Age 3 years 8 months
• Parents/nursery concerned re Vision
• RVA 1.0 (6/60) LVA 0.9 (6/48) Kays
• Surprisingly low VAs
• Straight eyes
• Normal Ophthalmological examination
• Refraction
• R 7.00 DS L 7.50 DS
• Reduced prescription issued R 5.00 L 5.50

21
Case Three Unexplained reduced VAs

• 3/12 Review
• Glasses worn full time
• R and LVA 0.65 (6/24-2) Kays
• Straight eyes
• Seen regularly to monitor VA
• Full prescription of R 6.00 L 6.50 issued at
  annual refraction
• Cooperation/concentration with VA test always
  noted to be poor
• VAs remained reduced for age
• Didnt appear to be overplussed

22
Case Three Unexplained reduced VAs

• Age 5 years
• R and LVA 0.5 (6/19) BL
• (sgls R and LVA 0.7 (6/30))
• Still no increase in VA if lenses decreased.
• Glasses still worn fulltime
• A comments that VA better cgls.
• Still no Ophthalmological abnormalities
• Age 5 ½ years
• Now has small RCS and R amblyopia
• RVA 0.62 (6/24-1) LVA 0.44 (6/15-2) BL

23
Case Three Unexplained reduced VAs

• Electrodiagnostic Tests performed
• VEPs and ERGs entirely normal in each eye
• So normal, retinal, macular and optic nerve
  function in each eye
• Parents commented that VA had also been tested
  and found to be normal
• Single optotype test used
• A now struggling at school
• Almost 6 years old
• Reading difficulties
• Difficulties seeing whiteboard

24
Case Three Unexplained reduced VAs

• Age 6 years
• RVA 0.7 (6/30) LVA 0.3 (6/12) Keeler cr
• RVA 0.4 (6/19) LVA 0.1 (6/7.5) Keeler ucr
• Reading assessed
• Guesses words
• Rubs eyes
• Blinks excessively
• Difficult for A to describe if symptoms present
• Coloured Overlay
• Appeared to prefer orange and acqua overlays

25
Case Three Unexplained reduced VAs

• Age 6 ½ years
• R amblyopia being treated
• RVA 0.54 (6/19-2) LVA 0.34 (6/12-2) BL
• RVA 0.45 (6/15-2) LVA 0.15 (6/7.5-2) K ucr
• Doing much better at school
• Now has extra help at school and home
• Uses orange overlay
• Uses bigger print
• Sits closer to whiteboard
• Review ongoing

26
Case Four Asthenopic Symptoms

• 14 year old girl
• Symptoms of difficulties including eye strain
  and headaches when reading
• CI and Accommodation insufficiency treated with
  exercises
• Symptoms remained despite satisfactory Conv and
  Accomm
• All symptoms relieved when issued with coloured
  overlay

27
Which patients can be helped?

• Dyslexia
• Meares Irlen Syndrome/Visual Stress
• Migraine
• Autistic Spectrum Disorder
• MS
• Parkinson's
• Others?

28
Vision Tests
29
Coloured Overlays
30
Coloured Overlay Spectrum
31
Coloured lenses
32
Conclusions.

• Reading difficulties and visual symptoms can
  present at all ages
• Be aware of other possible diagnoses
• Importance of observation
• Detailed questioning re reading skills/ability at
  school
• Patients may not just have one problem
• Keep an open mind Think outside the Box

33

• Any questions?

34

• Thank You.